1. PRESENTATION ON
SENSORS
PRESENTED BY:
SHASHANK SONI
13MT07IND016
M.Tech (Industrial Engg), Sem II

2. What is a Sensor?
 A device that measures a physical variable (e.g.
force, pressure, temperature, velocity, flow rate,
etc.)
 And converts the physical quantity into another
form
 Which can be read by an observer or by an
instrument.
 The most common conversion is to electrical form
as the converted signal is more convenient to use
and evaluate.

3. General Electronic Sensor
• Primary Transducer: changes “real world” parameter into electrical signal
• Secondary Transducer: converts electrical signal into analog or digital
values
Typical Electronic Sensor System
usable
values
real
world
analog
signal
primary
transducer
secondary
transducer
sensor
microcontroller
signal processing
communication
sensor
input
signal
(measurand)
sensor data
analog/digital
network
display

4. Desirable features of sensors
 Accuracy
 Precision
 Operating range
 Speed of response
 Calibration
 Reliability
 Cost and ease of operation
 Resolution

5. Accuracy vs. Precision
Precision without
accuracy
Accuracy without
precision
Precision and
accuracy

6. 
internal information
What is the angle of my arm?
Why Sensors are Required?

7. Where am I?
localization
?
Why Sensors are Required?

8. Will I hit anything?
obstacle detection
Why Sensors are Required?

9. Autonomous material handling
Where are the forkholes?
Why Sensors are Required?

10. Where is the face?
Face detection & tracking
Why Sensors are Required?

11. Sensors used in Robotics
The sensors used in robotics include a wide range of
devices which can be divided into following categories:
 Tactile Sensors
 Proximity and Range sensors
 Miscellaneous sensors and sensor based
systems
 Machine vision systems

12. Tactile Sensors
 Tactile sensors are devices which indicate contact
between themselves and some other solid object.
 Tactile sensing devices can be divided into two
classes: Touch sensors and Force sensors.

13. Touch Sensors
force voltage
measurement
electrical flow
a simple
switch
• Touch sensors provide a binary output signal
which indicates whether or not contact has been
made with the object without regard to the
magnitude of the contacting force.

14. Force Sensing
• Force sensor (also known as stress sensor)
indicate not only that contact has been made
with the object but also the magnitude of the
contact force between the two objects.
 Metal foil strain-gauge based (load cell)
 Good in low frequency response
 High load rating
 Resolution lower than piezoelectricity-based
 Rugged, typically big size, heavy weight

15. Force Sensing
 Piezoelectricity based (force sensor)
 lower cutoff frequency at 0.01 Hz
 can NOT be used for static load measurement
 Good in high frequency
 High resolution
 Limited operating temperature (can not be
used for high temperature applications)
 Compact size, light

16. Proximity and Range Sensors
 Proximity sensors are devices that indicate when
one object is close to another object.
 Some of these sensors can also be used to measure
the distance between the object and the sensor, and
these devices are called Range sensors.
 Range sensors would be useful for determining the
location of an object(e.g., the work part) in relation
to robot.

17. Types of Proximity and Range
Sensors

18. Eddy Current Detector
device that emits an alternating magnetic field
at the tip of a probe, which induces eddy
currents in any conductive object in the range
of the device.

19. Photometric sensor
 used to sense light. category includes photocells ,
photoelectric transducers ,photo tubes,
phototransistor and photoconductors. Can be used
to indicate presence or absence of an object.

20. Optical Pyrometer
device used to measure high temperatures by
sensing the brightness of an object’s surface.
Can be used to indicate presence or absence of
an object.

21. Vacuum Switches
 device used to indicate negative air pressures.
Can be used with a vacuum gripper to indicate
presence or absence of an object.

22. Miscellaneous Sensors and Sensor
Based Systems
 The miscellaneous category covers the remaining
types of sensors that might be used for interlocks
and other purposes in manufacturing work cells.
 This category includes devices with the capability
to sense variables such as temp., pressure, fluid
flow, and electrical properties.

23. Types of Miscellaneous Sensor
• Ammeter: Electrical meter used to measure electrical
current.
• Linear variable differential transformer:
Electromechanical transducer used to measure linear
or angular displacement.
• Ohmmeter: used to measure electrical resistance.
• Potentiometer: Electrical meter used to measure
voltage.

24. Types of Miscellaneous Sensor
• Piezoelectric accelerometer: sensor used to indicate or
measure vibration.
• Pressure transducer: Various transducers used to
indicate air pressure and other fluid pressures.
• Thermistor : device based on electrical resistance used
to measure temperatures.
• Thermocouple: used to measure temperatures. Based
on the principle that a junction of two dissimilar metals
will emit an emf which can be related to temperatures.

25. Machine Vision System
 Vision sensors: Advanced sensor system used
together with pattern recognition and other
techniques to view and interpret events
occuring in the robot workplace.

26. Magnetic Field Sensor
 Magnetic Field sensors
are used for power
steering, security, and
current measurements
on transmission lines
 Hall voltage is
proportional to
magnetic field
x x x x x x
x x x x x x
x x x x x x
+ + + + + + + + + + + + + + +
- - - - - - - - - - - - - - -
I (protons) +
VH
-
B
tqn
BI
VH




27. Ultrasonic Sensor
 Ultrasonic sensors are used
for position measurements
 Sound waves emitted are in
the range of 2-13 MHz
 Sound Navigation And
Ranging (SONAR)
 Radio Detection And
Ranging (RADAR) –
ELECTROMAGNETIC WAVES
15° - 20°

28. Applications of Sensors in
Manufacturing
 Distance sensing
 Contour Tracking
 Machine Vision / Pattern recognition
 Machine diagnosis
 Process Parameter sensing
 Safety monitoring
 Parts inspection for quality control

29. Distance Sensing
• Sensors for such application are of two types,
either contact type or non contact type.
•Contact type sensors are like dial gauge, gauge
blocks, pins, etc. However these sensors have a
limitation of wear and tear, and are not very
commonly used.
•Non contact types may be inductive, acoustic,
capacitive or optical sensors.

30. Contour tracking:
This is a kind of scanning process and is performed
by using electrical sensors such as inductive and
capacitive ones and optical sensors mostly laser
based scanners.
Machine Vision:
Here also tactile arrays and ultrasonic scanning
serve some useful purpose. Besides optical systems
with binary vision, grey level sensing and
stereovision are widely used.

31. Machine Diagnosis:
Well known sensors are used to measure forces,
torque, strain, frequency and a lot of other
indirect diagnostic data.
Process Parameters Monitoring:
Parameters such as pressure, force, speed,
temperature, fluid levels, chemical composition
and pH value data are measured in different
environmental conditions.

32. END OF PRESENTATION